1. 16.1-2
Microbial Ecology

2. 16.1 Microbes & Ecosystem Niches
Microbes live in all parts of the biosphere
100,000,000 times more microbes than observable stars
Microbes have a huge impact upon Ecology. No Microbes = No Life
Photosynthesis, production, decomposition, fixation, bioremediation and biotechnology
Each microbial species occupies a unique niche
Chemoautotrophs, chemoheterotrophs, photoautotrophs, photoheterotrophs and others.
Microbiology
16.1 Microbial Ecology

3. 16.1 Organization of Ecosystems
Microbes are critical at all trophic levels as producers, consumers and decomposers.
Microbiology
16.1 Microbial Ecology

4. 16.1 Microbes in the Biogeochemical Cycles
Microbes convert energy and matter from one form to another so that other organisms can get the energy and nutrients they need to survive.
Microbiology
16.1 Microbial Ecology

5. Microbiology
16.1 Microbial Ecology

6. Microbiology
16.1 Microbial Ecology

7. Microbiology
16.1 Microbial Ecology

8. Microbiology
13.1 Microbial Ecology

9. Microbiology
16.1 Microbial Ecology

10. 16.2 Soil Composition
The composition of the soil determines how much organic matter it can produce.
Microbes make up about 1% of the soil.
Microbes convert and release nutrients which can then be absorbed and used by other organisms.
Microbiology
16.2 Soil & Plant Microbiology

11. 16.2 Physical Properties of Soil
There are distinct layers or horizons:
O horizon-topsoil
A horizon-organic/inorganic mixture
B horizon-subsoil
C horizon-soil base
Bedrock-below C horizon
Microbiology
16.2 Soil & Plant Microbiology

12. 16.2 Mycorrhiza
Symbiotic association between a fungus and the roots of vascular plants.
Release minerals from the soil so that they can then be absorbed by plants
Microbiology
16.2 Soil & Plant Microbiology

13. 16.2 Wetland Soils Most biologically diverse. Anaerobic Processes
Denitrification-Nitrogen
Sulfate reduction- Hydrogen Sulfide
Methanogenesis-Methane
Microbiology
16.2 Soil & Plant Microbiology

14. 16.2 Endophytes & Plants Mutualistic microbe found in all plants.
Protect from disease
Produce chemicals that inhibit the growth of competitors
Increase plant growth
Help plants survive heat and drought
Microbiology
16.2 Soil & Plant Microbiology

15. 16.2 Plant Pathogens Four Factors: Cell wall degrading enzymes Toxins
Phytohormones
Effector proteins
Microbiology
16.2 Soil & Plant Microbiology

16. 16.2 Nitrogen Fixation
78% of atmosphere is Nitrogen (N2) but cannot be used by plants or animals.
Nitrogen fixing bacteria in a symbiotic relationships in certain types of plant roots nodules (legumes) can convert N2 into compounds which the plants can use.
Microbiology
16.2 Soil & Plant Microbiology